diff --git a/95_Weekday/javascript/weekday.js b/95_Weekday/javascript/weekday.js
index 2e1129a0..653b3de3 100644
--- a/95_Weekday/javascript/weekday.js
+++ b/95_Weekday/javascript/weekday.js
@@ -36,9 +36,9 @@ function tab(space) {
 }
 
 class DateStruct {
-    year;
-    month;
-    day;
+    #year;
+    #month;
+    #day;
 
     /**
      * Build a DateStruct
@@ -47,9 +47,25 @@ class DateStruct {
      * @param {number} day
      */
     constructor(year, month, day) {
-        this.year = year;
-        this.month = month;
-        this.day = day;
+        this.#year = year;
+        this.#month = month;
+        this.#day = day;
+    }
+
+    get year() {
+        return this.#year;
+    }
+
+    get month() {
+        return this.#month;
+    }
+
+    get day() {
+        return this.#day;
+    }
+
+    clone = () => {
+        return new DateStruct(this.#year, this.#month, this.#day)
     }
 
     /**
@@ -58,14 +74,14 @@ class DateStruct {
      * see https://en.wikipedia.org/wiki/Gregorian_calendar
      * @returns {boolean} true if date could be Gregorian; otherwise false.
      */
-    isGregorianDate() {
+    isGregorianDate = function () {
         let result = false;
-        if (this.year > 1582) {
+        if (this.#year > 1582) {
             result = true;
-        } else if (this.year === 1582) {
-            if (this.month > 10) {
+        } else if (this.#year === 1582) {
+            if (this.#month > 10) {
                 result = true;
-            } else if (this.month === 10 && this.day >= 15) {
+            } else if (this.#month === 10 && this.#day >= 15) {
                 result = true;
             }
         }
@@ -76,15 +92,15 @@ class DateStruct {
      * Returns a US formatted date, i.e. Month/Day/Year.
      * @returns {string}
      */
-    getFormattedDate() {
-        return this.month + "/" + this.day + "/" + this.year;
+    toString = function () {
+        return this.#month + "/" + this.#day + "/" + this.#year;
     }
 }
 
 class Duration {
-    years;
-    months;
-    days;
+    #years;
+    #months;
+    #days;
 
     /**
      * Build a Duration
@@ -93,9 +109,70 @@ class Duration {
      * @param {number} days
      */
     constructor(years, months, days) {
-        this.years = years;
-        this.months = months;
-        this.days = days;
+        this.#years = years;
+        this.#months = months;
+        this.#days = days;
+    }
+
+    get years() {
+        return this.#years;
+    }
+
+    get months() {
+        return this.#months;
+    }
+
+    get days() {
+        return this.#days;
+    }
+
+    clone = () => {
+        return new Duration(this.#years, this.#months, this.#days)
+    }
+
+    /**
+     * Adjust Duration by removing years, months and days from supplied Duration.
+     * This is a naive calculation which assumes all months are 30 days.
+     * @param {Duration} timeToRemove
+     */
+    remove = (timeToRemove) => {
+        this.#years -= timeToRemove.years;
+        this.#months -= timeToRemove.months;
+        this.#days -= timeToRemove.days;
+        if (this.#days < 0) {
+            this.#days += 30;
+            this.#months--;
+        }
+        if (this.#months < 0) {
+            this.#months += 12;
+            this.#years--;
+        }
+    }
+
+    toString = () => {
+        return this.#years + "/" + this.#months + "/" + this.#days;
+    }
+
+    /**
+     * Determine approximate Duration between two dates.
+     * This is a naive calculation which assumes all months are 30 days.
+     * @param {DateStruct} date1
+     * @param {DateStruct} date2
+     * @returns {Duration}
+     */
+    static between(date1, date2) {
+        let years = date1.year - date2.year;
+        let months = date1.month - date2.month;
+        let days = date1.day - date2.day;
+        if (days < 0) {
+            months--;
+            days += 30;
+        }
+        if (months < 0) {
+            years--;
+            months += 12;
+        }
+        return new Duration(years, months, days);
     }
 }
 
@@ -140,25 +217,6 @@ function printTimeSpent(duration) {
     print(duration.years + "\t" + duration.months + "\t" + duration.days + "\n");
 }
 
-/**
- * Adjust unaccounted time by remove years, months and days supplied.
- * @param {Duration} unaccountedTime
- * @param {Duration} timeToRemove
- */
-function adjustUnaccountedTime(unaccountedTime, timeToRemove) {
-    unaccountedTime.years -= timeToRemove.years;
-    unaccountedTime.months -= timeToRemove.months;
-    unaccountedTime.days -= timeToRemove.days;
-    if (unaccountedTime.days < 0) {
-        unaccountedTime.days += 30;
-        unaccountedTime.months--;
-    }
-    if (unaccountedTime.months <= 0) {
-        unaccountedTime.months += 12;
-        unaccountedTime.years--;
-    }
-}
-
 /**
  * Determine if the given year is a leap year.
  * @param year
@@ -193,7 +251,7 @@ function getDayOfWeek(date) {
     const yearInCenturyOffsets = yearInCentury / 4 + yearInCentury;
 
     // combine offsets with day and month
-    let dayOfWeek = centuryOffset +  yearInCenturyOffsets + date.day + COMMON_YEAR_MONTH_OFFSET[date.month-1];
+    let dayOfWeek = centuryOffset + yearInCenturyOffsets + date.day + COMMON_YEAR_MONTH_OFFSET[date.month - 1];
 
     dayOfWeek = Math.floor(dayOfWeek % 7) + 1;
     if (date.month <= 2 && isLeapYear(date.year)) {
@@ -254,28 +312,6 @@ function getNormalisedDay(date) {
     return (date.year * 12 + date.month) * 31 + date.day;
 }
 
-/**
- * Determine approximate difference between two dates.
- * This is a naive calculation which assumes all months are 30 days.
- * @param {DateStruct} date1
- * @param {DateStruct} date2
- * @returns {Duration}
- */
-function difference(date1, date2) {
-    let years = date1.year - date2.year;
-    let months = date1.month - date2.month;
-    let days = date1.day - date2.day;
-    if (days < 0) {
-        months--;
-        days += 30;
-    }
-    if (months < 0) {
-        years--;
-        months += 12;
-    }
-    return new Duration(years, months, days);
-}
-
 // Main control section
 async function main() {
     print(tab(32) + "WEEKDAY\n");
@@ -300,19 +336,18 @@ async function main() {
         const normalisedToday = getNormalisedDay(today);
         const normalisedDob = getNormalisedDay(dateOfBirth);
 
-        const dateOfBirthText = dateOfBirth.getFormattedDate();
         let dayOfWeekText = getDayOfWeekText(dateOfBirth);
         if (normalisedToday < normalisedDob) {
-            print(dateOfBirthText + " WILL BE A " + dayOfWeekText + "\n");
+            print(dateOfBirth + " WILL BE A " + dayOfWeekText + "\n");
         } else if (normalisedToday === normalisedDob) {
-            print(dateOfBirthText + " IS A " + dayOfWeekText + "\n");
+            print(dateOfBirth + " IS A " + dayOfWeekText + "\n");
         } else {
-            print(dateOfBirthText + " WAS A " + dayOfWeekText + "\n");
+            print(dateOfBirth + " WAS A " + dayOfWeekText + "\n");
         }
 
         if (normalisedToday !== normalisedDob) {
             print("\n");
-            let differenceBetweenDates = difference(today, dateOfBirth);
+            let differenceBetweenDates = Duration.between(today, dateOfBirth);
             if (differenceBetweenDates.years >= 0) {
                 if (differenceBetweenDates.days === 0 && differenceBetweenDates.months === 0) {
                     print("***HAPPY BIRTHDAY***\n");
@@ -323,19 +358,19 @@ async function main() {
                 printTimeSpent(differenceBetweenDates);
                 const approximateDaysBetween = (differenceBetweenDates.years * 365) + (differenceBetweenDates.months * 30) + differenceBetweenDates.days + Math.floor(differenceBetweenDates.months / 2);
                 // Create an object containing time unaccounted for
-                const unaccountedTime = {...differenceBetweenDates};
+                const unaccountedTime = differenceBetweenDates.clone();
 
                 // Calculate time spent in the following functions.
                 print("YOU HAVE SLEPT \t\t\t");
                 const sleepTimeSpent = time_spent(0.35, approximateDaysBetween);
                 printTimeSpent(sleepTimeSpent);
 
-                adjustUnaccountedTime(unaccountedTime, sleepTimeSpent);
+                unaccountedTime.remove(sleepTimeSpent);
                 print("YOU HAVE EATEN \t\t\t");
                 const eatenTimeSpent = time_spent(0.17, approximateDaysBetween);
                 printTimeSpent(eatenTimeSpent);
 
-                adjustUnaccountedTime(unaccountedTime, eatenTimeSpent);
+                unaccountedTime.remove(eatenTimeSpent);
                 if (unaccountedTime.years <= 3) {
                     print("YOU HAVE PLAYED \t\t\t");
                 } else if (unaccountedTime.years <= 9) {
@@ -346,7 +381,7 @@ async function main() {
                 const workPlayTimeSpent = time_spent(0.23, approximateDaysBetween);
                 printTimeSpent(workPlayTimeSpent);
 
-                adjustUnaccountedTime(unaccountedTime, workPlayTimeSpent);
+                unaccountedTime.remove(workPlayTimeSpent);
                 if (unaccountedTime.months === 12) {
                     unaccountedTime.years++;
                     unaccountedTime.months = 0;